Switch construction



Sept. 27, 1960 s. l. LINDELL SWITCH CONSTRUCTION 6 Sheets-Sheet 1 FiledSept. 25, 1958 INYENTOR. fi QA/dflUZdZL BY M W 4% watikwkq rwmmm 33%Sept. 27, 1960 s. l. LINDELL 2,954,449

- SWITCH CONSTRUCTION Filed Sept. 25, 1958 I s Sheets-Sheet 2 A7/M50L/47/0/V g 79 63 6 f g3 M INVENTOR.

Sept. 27, 1960 s. l. LINDELL 2,954,449

SWITCH CONSTRUCTION Filed Sept. 25. 1958 6 Sheets-Sheet a INVENTOR.

Sept. 27, 1960 s. LINDELL 2,954,449

SWITCH CONSTRUCTION Filed Sept. 25, 1958 6 Sheets-Sheet 4 INYENTOR.

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SWITCH CONSTRUCTION Filed Sept. 25, 1958 6 Sheets-Sheet 6 INVENTOR. flguraflazdefli nited States Patent SWITCH-CONSTRUCTION Sigurd I. Lindeil,Chicago, Ill., assignor to S & C Electric Company, Chicago, lll.,vacorporation of Delaware Filed Sept. 25, 1958,,Ser. No. 763,383

6 Claims. (Cl; 200146) This invention relates, generally, to'theconstruction of load break disconnecting switches and it: has particularrelation to the sequence of operation'tliereof. This invention is animprovement over the invention disclosed in application Serial No;748,912, filed July 16, 1958, and assigned to the assignee of thisapplication.

In the copending application above referred to there is disclosed adisconnectingswitch construction provided with a load currentinterrupter. The load current interrupter is intended for eifecting thefinal opening of the circuit after the switch blade is moved out ofengagement with a cooperating stationary contact. After this takes placeand the switch blade has been moved well beyond the distance where anarc might restrike between the switch blade and the. stationary contact,the load current interrupter is operated to' open the circuit in suchmanner that no external arc is drawn. The contacts of the load currentinterrupter are arranged and constructed to interrupt satisfactorilyload currents up to the normal load current carrying capacity of thedisconnecting switch. When the switch blade is swung to the closedposition, there is the possibility'that the circuit may be completed ona fault. In that case current flow will take place substantially inexcess ofth'e normal load current flow through the'switch. Since thecontacts of the load current interrupter are intended to conduct normalload current only momentarily when the switch is being opened and tointerrupt the same, severe damage may be incurred by these contacts ifthe switch should be closed under short circuit conditions and thecircuit first completed through the contacts of the load currentinterrupter. In accordance with the construction disclosed in thecopending application, provision is made for closing the contacts of theload current interrupter as the switch blade approaches the switchclosed position. Provided that the movement of the switch blade towardthe closed position is sufiiciently slow, the circuit will be completedfirst between the switch blade and the stationary switch contact andwill not be completed at the contacts of the load current interrupter.However, if the switch blade is moved rapidly toward the switch closedposition, which is desirable in order to limit the duration of arcing atthe contact engaged by the blade, and the movable contact of the loadcurrent interrupter is initiated in its movement toward the closedposition, the energy imparted thereto by impact of the fast movingswitch blade assembly may be sufficient to cause the movable contact tomove in advance of the movement of the switch blade such that thecircuit will be completed at the contacts of the load currentinterrupter.

Accordingly, among the objects of this invention are:

To provide for initiating the closure of the contacts of r the loadcurrent interrupter only after the switch blade has been swung towardthe closed position sufliciently far to positively establish the circuittherethrough at the voltage' at which the switch is intended tooperate;to: engage the: closing trigger of the load current interrupter onlyafter the switch blade has been swung toward the closed positionsufliciently far to'complete the circuit toa stationary contact by anare initiated at the voltage at which the switch is intended to operate;to operate the switch blade by a mechanism that moves it quickly andpositively to the switch closed position; and to operate the interruptercontacts from the fully open position to the closed position after thecircuit has been established through the switch blade and a stationarycontact in combination with means for positively opening the interruptercontacts after the switch blade has been disengaged from the stationarycontact.

Other objects of this invention'will, in part, be obvious and in partappear hereinafter.

This invention is disclosed in the embodiment thereof shown in theaccompanying drawings and it comprises the features of'construction,combination of elements and arrangement of parts that will beexemplified in the construction hereinafter set forth and the scope oftheapplication of which will be indicated in the appended claims.

For a more complete understanding of the nature and scope of thisinvention reference can be had to the following detailed description,taken together with the accompanying drawings, in which:

Figure l is a view, in front elevation, of a three phase loadinterrupter switch installation in each pole of which the presentinvention is embodied;

Figure 2 is a view, in side elevation, showing one pole of the threephase load interrupter switch installation, shownin Figure l, certainparts being broken away and others being shown in section in order toillustrate more clearly the details of construction;

Figure 3 is a view, partly in side elevation and principally in verticalsection, showing the details of construction of the load interrupter,the illustration showing the contactsof'the load interrupter in theclosed position;

Figure 4 is a view, similar to Figure 3, but showing the loadinterrupter contacts in the open position;

Figure 5 is a view, similar to Figure 2', but showing the switch bladebeing moved toward the open-positionwith the opening cam engaging:the-opening trigger of the load current interrupter, no movement of themovable contact of the load current interrupter having taken place;

Figure 6 is a view, similar to Figure 2, but showing the switch blade inthe full open position with the triggers of the load current interruptershown in the positions that they occupy when the movable contact of theload current interrupter is in the open position as shown in Figure 4;

Figure 7 is a view, similar to Figure 2, but showing the switch bladebeing moved toward the switch closedposition to a location where an arccan be struck between it and the stationary switch contact at thevoltage at which the switch is intended to operate with the closing camengaging the closing trigger of the load current interrupter but nomovement of the movable contact thereof having taken place from theposition shown in Figure 4; and

Figure 8' is a top plan view taken generally along the line 8-8 ofFigure 7 and showing the relationship between the contact tip on thestationary switch contact and the arcing contact buttons carried by theswitch blade at the time that the latter has been moved within strikingdistance of the stationary switch contact.

Referring now particularly to Figure l of the drawings, it will beobserved that the reference character 10 designates, generally, a frameformed of structural rolled steel sections that may include frameuprights 11 and 12 on which insulating barriers 13 are mounted. It willbe noted that the insulating barriers 13. are positioned between loadinterrupter disconnecting switches each of which is indicated,generally, at 14. Three disconnecting switches 14 are employed for athree phase installation.

Where single phase operation is required it will be understood that onlya single load interrupter disconnecting switch 14 is used. Since theconstruction of the load interrupter disconnecting switches 14 isidentical for each, a description of one will suffice for all of them.

The load interrupter disconnecting switches 14 are mounted on upper andlower transverse angle members 15 and 16 which are secured suitably tothe frame uprights 11 and 12 at their ends. It will be understood thatother mounting means can be employed if desired. Upper and lowerinsulators 17 and 18 are provided for each load interrupterdisconnecting switch 14 and they are secured by bolts 19 and 20 to theupper and lower transverse angle members 15 and 16 as shown.

At their outer ends the upper and lower insulators 17 and 18 havesecured thereto upper and lower line terminals that are indicated,generally, at 21 and 22 respectively. The terminal members 21 and 22 areprovided with terminal pads 23 and 24 to permit connection of lineconductors. The upper line terminal has a contact tongue 25 formedintegrally therewith and projecting outwardly therefrom while the lowerline terminal 22 has a hinge member 26 formed integrally therewith andprojecting outwardly therefrom. The upper and lower line terminals 21and 22 are arranged to be interconnected by a switch blade that isindicated, generally, at 27 and is pivoted at 28 to the hinge member 26.The switch blade 27 preferably is formed by a pair of switch blademembers 29 and 30 that are spaced apart a substantial distance for theprincipal portion of their length and engage opposite sides of the hingemember 26 at their lower ends. Each switch blade member near its upperend is bent inwardly as indicated at 31 in Figure 1 to provide a contactsection 32 at the upper end with these contact sections being arrangedto engage opposite sides of the contact tongue 25 which is relativelythin as compared to the width of the hinge member 26. It will be pointedout hereinafter wherein additional arcing contact construction isprovided at the upper end of the switch blade 27 for each of the loadinterrupter disconnecting switches 14 to insure that the circuit iscompleted between the contact tongue 25 and the switch blade 27 when thelatter is moved to the closed position before the circuit is completedthrough a load current interrupter to be described. It will beunderstood that the insulators 17 and 18 are mounted on the frame 10 inthe manner described and serve to position the upper and lower lineterminals 21 and 22 in insulated spaced relation and that the switchblade 27 is arrranged to interconnect them when it is in the closedposition as shown in Figures 1 and 2 of the drawings.

It is desirable that an operating mechanism be provided for quicklymoving the switch blade 27 from the switch closed position shown inFigures 1 and 2 of the drawings to the open position shown in Figure 6and for quickly swinging it to the closed position for completing thecircuit in order to limit the duration of arcing on opening and closingof the circuit. For this purpose a quick make quick break operatingmechanism indicated at 33 in Figure 1 is employed. This mechanism can bemotor operated or it can be spring driven and manually actuated as maybe desired. The specific arrangement and construction of the quick makequick break operating mechanism 33 form no part of the present inventionother than to point out that such a mechanism is employed which iscapable of moving the switch blade 27 from and to the switch closedposition relatively rapidly and to insure complete closing movement ofthe switch blade 27 and limit arcing during such closing movement andclosing of the contacts of the load current interrupter (to bedescribed) automatically once the circuit has been established throughthe switch blade and contact tongue 25. This provides for fullcontinuous current carrying capacity of the switch and for interruptionof load current by the load current interrupter in proper sequence 4when the operation of the mechanism takes place in opposite direction toopen the switch.

For interconnecting the quick make quick break operating mechanism 33and each switch blade 27 of the three load interrupter disconnectingswitches 14 three links 35 of a suitable insulating material are used.At one end each link 35 is pivoted at 36 to the respective blade switchblade 27. At its other end each link 35 is pivoted at 37 to an arm 38.The arms 38 are secured to a horizontally extending shaft 39 which isjournaled on the frame 10 in suitable bearings 40 which can be mountedon the frame uprights 11 and 12. The shaft 39 extends to have operativeconnection with the quick make quick break operating mechanism 33 whichis capable, as pointed out above, of rotating the shaft 39 in onedirection to simultaneously open the switch blades 27 and in theopposite direction to close them simultaneously, in each instance at arelatively high speed.

When each switch blade 27 is moved to the open position, it isundesirable that any are be formed between it and its upper lineterminal 21. More specifically, it is desired that no are be formedunder these conditions between the contact sections 32 and the contacttongue 25. Accordingly, the upper line terminal 21 is provided with adepending contact plate 43 and an integrally formed socket 44 withrespect to which a load current interrupter, shown generally at 45, isdetachably secured by a bolt 46 as described in US. Patent No.2,621,272, issued December 9, 1952.

Figures 3 and 4 of the drawings show the details of construction of theload current interrupter 45. There it will be observed that it includesa contact plate 47 which is arranged to overlie the depending contactplate 43 and to be secured thereto by the bolt 46. Threaded into thelower portion of the contact plate '47 is a metallic plug sleeve 48which is provided at its inner end with a stationary load interruptercontact 49. Since the contact plate 47 is secured to the contact plate43 which is formed integrally with the upper line terminal 21 and sincethe plug sleeve 48 is threaded into the contact plate 47, the stationaryload interrupter contact 49 is connected directly to the upper lineterminal 21.

The load current interrupter 45 also includes a movable load interruptercontact 50 Which, as shown in Figure 3 of the drawings, is in contactengagement with the stationary contact 49 when the load interrupter 45is in the closed position and the switch blade 27 also is in the closedposition. The movable contact 50 is carried at one end of a contact rod51 that is pivoted at 52 at its other end to an operating mechanismwhich is indicated, generally, at 53. The operating mechanism 53 iscontained within a metallic housing 54 and it includes a link 55 towhich the contact rod 51 is pivoted at 52. The other end of the link 55is pivoted at 56 to one end of a link 57 and the other end is pivoted at58 to the housing 54. Formed integrally with the link 57 is a stop 59which limits the movement of the operating mechanism 53 in either theclosing or opening direction. livoted at 6t intermediate the pivots 52and 56 on the link is an arm 61 the other end of which is fastened tothe rock shaft 62 that is journaled on the housing 54 with its endsprojecting therethroug h to opposite sides. At one end of the rock shaft62 there is fastened a closing trigger 63 which is shown by full linesin Figures 2, 5, 6 and 7 of the drawings and by broken lines in Figure3. At the other end of the rock shaft 62 there is an opening trigger 64which is angularly spaced, as shown in Figure 3, from the closingtrigger 63. A toggle spring 65 interconnects the pivots 56 and the rockshaft 62 for the pur-- pose of providing a snap action in the movementof the contact rod 51 and for holding it in either the closed positionshown in Figure 3 or the open position shown in Figure 4 of thedrawings.

Any are that is formed on separation of the movable load interrupterontat 50 from the stationary load inana yses terrupter contact as isdrawn in a bore 66 that is formed in a stack 67 of fiber washers whichare surrounded by an insulating sleeve 68. One end of the insulatingsleeve 68 is threaded into the lower portion of the contact plate 47while the other end is threaded into a tubular extension from themetallic housing 54. Additional insulation is provided between thecontact plate 47 and the metallic housing 54 by a tubular porcelaininsulator 69. The are is confined within the bore 66 by a trailer 70that is formed of suitable insulating material and is connected to thecontact rod 51 and moves simultaneously with it and with the movablecontact 50. Since the only time that current flows through the contactrod 51 is during the circuit opening operation, it is-unnecessary toprovide an extremely low resistance path to the switch blade 27.Accordingly, the circuit extends from the contact rod 51 through thelinks 55 and 57 and 61 to the metallic housing 54. The circuit to theswitch blade 27 extends through a bow contact 73 that is carriedthereby, as indicated in Figure 2, and which is'arranged to engageprojections '74 on the metallic housing 54 during the time that theswitch blade is moved away from or toward the contact tongue 25 of theupper line terminal 21.

It will be recalled that the arrangement of the load current interrupter45 is such that the circuit is opened between the contacts 49 and 50when the switch blade 27 is swung'to the open position. In order toaccomplish this an opening cam 75, Figure 6, is secured by rivets 76 tothe switch blade member 30. The opening cam 75 has a cam surface 77 thatfaces away from the pivot axis 23 of the switch blade 27 and is arrangedto engage the left side of the opening trigger 64, as shown in'Figure 5,asthe switch blade 27 is swung to the open position. The continuedmovement of the switch blade 27 in the opening direction brings the bowcontact 73 into engagement with metallic housing 54 with the resultthat, before the contact sections 32 of the switch blade members 29 and3t disengage the contact tongue 25, a shunt circuit is providedtherebetween through the load interrupter 45. After a sufficient gap hasbeen introduced between the switch blade 27 and the contact tongue 25,the opening cam 75 engages the opening trigger 64. This positivelycausesthe rock shaft 62 to be rotated in a counterclockwise direction asviewed in Figure 3 of the drawings with the result that contact 50cannot fail to move out of engagement with the stationary contact 49 andthe arc is drawn and extinguished within the bore 66. Figure 4 of thedrawings shows the relative positions of the movable parts of the loadcurrent interrupter 45 when it is in the open position. It will be notedthat the opening trigger 64 has been swung in a counterclockwisedirection from its position shown in Figure 3 and that a correspondingmovement of the closing trigger 63 has taken place.

When the switch blade 27 is in the fully open position it can occupy theposition shown in Figure 6. Here the closing trigger 63 is shown in theposition that it occupies, as shown in Figure 4, when the load currentinterrupter 45 is in the open position.

As pointed out in the copending application above referred to, it isdesirable that the circuit not be closed through the load interrupter 45on initial engagement of the movable contact 5t? with the stationarycontact 49 in the load current interrupter 45 or when the switch blade27 comes close enough to the contact tongue 25 for an arc to be struckwhen the switch blade 27 is moved toward the closed position.Accordingly, as disclosed in the copending application, provision ismade for delaying the closing or" the load current interrupter 45 untilthe circuit has been completed between the switch blade 27 and thecontact tongue 25 of the upper line terminal 21. For this purpose thereis secured by rivets 78, Figure 2, to the switch blade member 29 and arm79 which extends from the switch blade 27 in the direction of openingmovement thereof. At the outer end of the arm 79 there is securedby'rivets itla closing c-a'm 81-Which has a cam surface SZ' tha-t facesoutwardly or away from the pivot axis 28'and is arranged to engage theright hand side of the closing trigger 63 when the switch blade 27 ismoved toward the closed position.

As pointed out hereinbefore, when the switch blade 2'7 is moved quicklytoward the switch closed position and the camsurface 32 of the closing81 engages the closing trigger 63', there is the possibility thatsufiicient energy may be imparted into the. operating mechanism 53,contact rod 51, movable load interrupter contact 59 and traiier 70 thatwill cause the movable load interrupter contact 56 to move in advance ofthe movement of the Switchblade 27 to such an extent that it willapproach the stationary load interrupter contact 49 and complete thecircuit before the circuit is completed between the switch blade 27 andthe contact tongue 25 on the upper line terminal 21} Under thesecircumstances the circuit is first completed-between the contacts 49 and5tl'of the load current interrupter 45 and, if the circuit is closed ona fault, substantially more current will flow through the contacts 49'and 50' than they are intended to carry. They become burned and pitted.In addition the heat of the arc incident to such operation may vaporizeadjacent portions of the stack of fiber washers 67 and cause the bore 66to be severely eroded, Then, before a subsequent operation of the loadinterrupter disconnecting switches 14 takes place, the load currentinterrupters 45 should be removed andrepaired.

in accordance with this invention provision is made for insuring thatunder no circumstances will the circuit be completed betweenthe'contacts 4-9'and 50 of the load current interrupter 55' before thecircuit is completed directly between the switch blade 27' and thecontact tongue 25 on the upper line terminal 21.

As shown more clearly in Figure 5 of the drawings the contact tongue 25is provided with an upwardly extending" contact extension 85' that hasan integrally formed arm 86 which extends toward the switch blade 27. Onthe under side of the arm 86 there is a cylindrical arcing contact tip87, formed of suitable are resisting material, and it is held in placeby a stainless steel cap screw 88; For cooperating with the cylindricalarcing contact tip 87 a pair ofarcing contact buttons $39 are providedasshown more clearly in Figure 8' of the drawings; The arcing contactbuttons 59, like the arcing contacttip .87, are forme'd'of'arc resistingmaterial and are arranged either to lightly engage opposite sides of thetip 87 or to movein close proximity thereto but not in mechanicalengagement therewith when the switch blade 27 is movedtoclosed'po'sition. They are held in place by bolts 90 on the upper ends91 of switch blade extensions 92; The switch blade extensions $2 haveoutstanding foot portions 93 which are secured by rivets 94 to theinwardly bent portions 31 of the switch blade members 29 and 30. Theauxiliary contact extension 85, arm 86' and'tip 37 not only permitinitiating the arc in conventional manner to limit the damage to thecontact tongue 25 in closing on a fault but also they provide for moretravel of the switch blade 27 to operate the load current interrupter toclosed position after the circuit is established by the arc.

When the switch blade 27 is in the switch closed position as shown inFigure 2 of the drawings, the circuit is completed through it betweenthe upper and lower terminals 21 and 22. When the switch blade 27 isswung toward the open position as indicated by the arrow 95, Figure 5,the bow contact 73 engages one of the pro jections 74 on the undersideof the metallic housing and thereby places the load current interrupter-35 in shunt with the upper line terminal 21 and switch blade 27. Theopening movement ofthe switch. blade 27 continues in the directionindicated by the arrow 95 until the cam surface 77 on the opening cam 75engages the left hand side of the opening trigger 64. At this time thedistance indicated at 96 between the arcing contact tip 87 and thenearest part of one or the other of the switch blade extensions 92 issuch that, if the circuit were at that time opened by the load currentinterrupter 45, no arc would be restruck directly between the switchblade 27 and the upper line terminal 21. Thereafter the opening movementof the switch blade 27 is accompanied by a rotation of the rock shaft 62and the circuit is opened by separation of the movable load interruptercontact 50 from the stationary load interrupter contact 49 within thebore 66 and the arc incident to such operation is there drawn andextinguished. The movement of the switch blade 27 as operated by thequick make quick break operating mechanism 33 continues to the full openposition shown in Figure 6 of the drawings. At this time the parts ofthe load current interrupter 45 are positioned as shown in Figure 4 ofthe drawings. When the quick make quick break operating mechanism 33 isenergized to move the switch blade 27 toward the closed position asindicated by the arrow 97 in Figure 7 of the drawings, the operationcontinues with the circuit remaining open until, as shown in Figure 8 ofthe drawings, the arcing contact buttons 89 approach the arcing contacttip 87 to the distance indicated at 98. The distance 98 from the arcingcontact tip 87 to one or the other of the arcing contact buttons 89 issuch that, at the rated voltage of the load interrupter disconnectingswitch 14, an arc will be initiated between one or the other of thearcing contact buttons 89 and the contact tip 87. In the event that thecircuit is being closed on a fault, the current flow through such an arcwill be of corresponding magnitude. Its duration will be relativelyshort for the reason that the switch blade 27 is moved at a high speedby the quick make quick break operating mechanism 33 to the switchclosed position.

At the time that the arcing contact buttons 89 are within arcingdistance, as indicated at 98, of the arcing contact tip 87, the camsurface 82 on the closing cam 81, Figure 7, first engages the right handside of the closing trigger 63. The arrangement is such that no movementof the closing trigger 63 or movement of the movable load interruptercontact 50 is initiated until the switch blade 27 has been swung to sucha position that the arcing contact buttons 89 are brought into arestriking distance 98 from the arcing contact tip 87. Thereafter,continued movement of the switch blade 27 in the direction indicated bythe arrow 97 is accompanied by movement of the closing trigger 63 andcorresponding movement of the movable load interrupter contact 50 backto the closed position shown in Figure 3. Since no movement of themovable load interrupter contact 50 is initiated until after the circuitis completed through the are established between one or the other of thearcing contact buttons 89 and the arcing contact tip 87, there is nopossibility that the circuit will be completed under fault currentconditions or any other conditions between the contacts 49 and 50 of theload current interrupter 45.

Since certain changes can be made in the foregoing construction anddifferent embodiments of the invention can be made without departingfrom the spirit and scope thereof, it is intended that all matter shownin the accompanying drawings and described hereinbefore shall beinterpreted as illustrative and not in a limiting sense.

What is claimed as new is:

1. A switch construction for opening and closing a high voltage currentcarrying circuit comprising, in combination, a pair of switch contactsin insulated spaced relation, a switch blade for bridging said switchcontacts and movable into and out of engagement with one of said switchcontacts, a load current interrupter including separable interruptercontacts and operating means for opening and closing said interruptercontacts, one of said interrupter contacts being electrically connectedto said one switch contact and the other interrupter contact beingelectrically connected to said switch blade during that portion of itsmovement into and out of engagement with and adjacent to said one switchcontact, means cooperating with said operating means on movement of saidswitch blade to open position to open said interrupter contacts aftersaid switch blade disengages said one switch Contact, means holding saidinterrupter contacts in open position after operation to open positionin response to said movement of said switch blade to open position,means on said switch blade for mechanically engaging said operatingmeans to overcome said holding means and initiate the closure of saidinterrupter contacts on movement of said switch blade toward closedposition only after said switch blade has been moved to a position wherea circuit is established between it and said one switch contact at thevoltage rating of the switch construction thereby positively preventingthe closure of said interrupter contacts and completion of a circuittherethrough prior to completion of the circuit between said switchblade and said one switch contact.

2. A switch construction for opening and closing a high voltage currentcarrying circuit comprising, in combination, a pair of switch contactsin insulated spaced relation, a switch blade for bridging said switchcontacts and movable into and out of engagement with one of said switchcontacts, a load current interrupter including separable interruptercontacts and operating means for opening and closing said interruptercontacts, one of said interrupter contacts being electrically connectedto said one switch contact and the other interrupter contact beingelectrically connected to said switch blade during that portion of itsmovement into and out of engagement with and adjacent to said one switchcontact, means cooperating with said operating means on movement of saidswitch blade to open position to open said interrupter contacts aftersaid switch blade disengages said one switch contact, means holding saidinterrupter contacts in open position after operation to open positionin response to said movement of said switch blade to open position,means on said switch blade for mechanically engaging said operatingmeans to overcome said holding means and initiate the closure of saidinterrupter contacts on movement of said switch blade toward closedposition only after said switch blade has been moved to a position wherea circuit is established between it and said one switch contact at thevoltage rating of the switch construction thereby positively preventingthe closure of said interrupter contacts and completion of a circuittherethrough prior to completion of the circuit between said switchblade and said one switch contact, and quick operating mechanismmechanically connected to said switch blade for positively moving itfrom open to closed position at such a speed that the time is relativelyshort during which an arc is maintained between said one switch contactand said switch blade before said switch blade has contact engagementwith said one switch contact.

3. A switch construction for opening and closing a high voltage currentcarrying circuit comprising, in combination, a pair of switch contactsin insulated spaced relation, a switch blade for bridging said switchcontacts and swingable into and out of engagement with one of saidswitch contacts, an arcing contact on said one switch contact extendingtherefrom in the direction of opening movement of said switch blade andfirst approached thereby on closing movement thereof, a load currentinterrupter including separable interrupter contacts and operating meansfor opening and closing said interrupter contacts, one of saidinterrupter contacts being electrically connected to said one switchcontact and the other interrupter contact being electrically connectedto said switch blade during that portion of its movement into and out ofengagement with and adjacent to said one switch contact, means on saidswitch blade cooperating with said operating means on movement of saidswitch blade to open position to open said interrupter contacts aftersaid switch blade disengages said arcing contact, means holding saidinterrupter contacts in open position after operation to open positionby said means on said switch blade, and means on said switch blade formechanically engaging said operating means to overcome said holdingmeans and initiate the closure of said interrupter contacts on movementof said switch blade toward closed position only after said switch bladehas swung to within arcing distance of said arcing contact at thevoltage at which the switch construction is tended to be operatedthereby positively preventing the closure of said interrupter contactsand completion of a circuit therethrough until after the circuit isestablished between said switch blade and said arcing contact.

4. A switch construction for opening and closing a high voltage currentcarrying circuit comprising, in combination, a pair of switch contactsin insulated spaced relation, a switch blade for bridging said switchcontacts and swingable into and out of engagement with one of saidswitch contacts, an arcing contact on said one switch contact extendingtherefrom in the direction of opening movement of said switch blade andfirst approached thereby on closing movement thereof, a load currentinterrupter mounted on the one switch contact and including separableinterrupter contacts and operating means for opening and closing saidinterrupter contacts, one of said interrupter contacts beingelectrically connected to said one switch contact and the otherinterrupter contact being electrically connected to said switch bladeduring that portion of its movement into and out of engagement with andadjacent to said one switch contact, means holding said interruptercontacts in open position after operation to open position by said meanson said switch blade, means on said switch blade for mechanicallyengaging said operating means to overcome said holding means andinitiate the closure of said interrupter contacts on movement of saidswitch blade toward closed position only after said switch blade hasswung to within arcing distance of said arcing contact at the voltage atwhich the switch construction is intended to be operated therebypositively preventing the closure of said interrupter contacts andcompletion of a circuit therethrough until after the circuit isestablished between said switch blade and said arcing contact, and quickoperating mechanism mechanically connected to said switch blade forpositively moving it from open to closed position at such a speed thatthe time is relatively short during which an arc is maintained betweensaid arcing contact and said switch blade before said switch blade hascontact engagement with said one switch contact.

5. A switch construction for opening and closing a high voltage currentcarrying circuit comprising, in combination, a pair of switch contactsin insulated spaced relation, a switch blade for bridging said switchcontacts comprising a pair of parallel spaced apart elongated blademembers swingable into and out of engagement with one of said switchcontacts, an arcing contact on said one switch contact extendingtherefrom in the direction of opening movement of said switch blade andfirst approached on opposite sides by a pair of arcing tips on saidswitch blade on closing movement thereof, a load current interruptermounted on said one switch contact and including separable interruptercontacts and operating means for opening and closing said interruptercontacts including a pair of triggers on said load current interrupterand spaced from said switch blade when closed in the direction ofopening movement thereof, one of said interrupter contacts beingelectrically connected to said one switch contact and the otherinterrupter contact being electrically connected to said switch bladeduring that portion of its movement into and out of engagement with andadjacent to said one switch contact, means on one of said blade memberscooperating with said operating means on movement of said switch bladeto open position to engage one trigger to open said interrupter contactsafter said arcing tips disengage said arcing contact, and means on theother blade member for mechanically engaging the other trigger toinitiate the closure of said interrupter contacts on movement of saidswitch blade toward closed position only after said switch blade hasswung to position at least one of said arcing tips within arcingdistance of said arcing contact at the voltage at which the switchconstruction is intended to be operated thereby positively preventingthe closure of said interrupter contacts and completion of a circuittherethrough until after the circuit is established between said onearcing tip and said arcing contact.

6. A switch construction for opening and closing a high voltage currentcarrying circuit comprising, in combination, a pair of switch contactsin insulated spaced relation, a switch blade for bridging said switchcontacts comprising a pair of parallel spaced apart elongated blademembers swingable into and out of engagement with one of said switchcontacts, an arcing contact on said one switch contact extendingtherefrom in the direction of opening movement of said switch blade andlast engaged between a pair of arcing tips thereon on opening movementthereof and first engaged therebetween on closing movement thereof, aload current interrupter mounted on said one switch contact andincluding separable interrupter contacts and operating means for openingand closing said interrupter contacts including a pair of triggers onsaid load current interiupter and spaced from said switch blade whenclosed in the direction of opening movement thereof, one of saidinterrupter contacts being electrically connected to said one switchcontact and the other interrupter contact being electrically connectedto said switch blade during that portion or" its movement into and outof engagement with and adjacent to said one switch contact, means on oneof said blade members cooperating with said operating means on movementof said switch blade to open position to engage one trigger to open saidinterrupter contacts after said arcing tips disengage said arcingcontact, means on the other blade member for mechanically engaging theother trigger to initiate the ciosure of said interrupter contacts onmovement of said switch blade toward closed position only after saidswitch blade has swung to position at least one of said arcing tipswithin arcing distance of said arcing contact at the voltage at whichthe switch construction is intended to be operated thereby positivelypreventing the closure of said interrupter contacts and completion of acircuit therethrough until after the circuit is established between saidone arcing tip and said arcing contact, and quick operating mechanismmechanically connected to said switch blade for positively moving itfrom open to closed position at such a speed that the time is relativelyshort during which an arc is maintained between said arcing contact andsaid one arcing tip before said switch blade has contact engagement withsaid one switch contact.

References Cited in the file of this patent UNITED STATES PATENTS2,351,826 Lindell et a1. June 20, 1944 2,469,203 Palme et a1 May 3, 19492,480,622 Warnock Aug. 30, 1949 2,712,577 Stene July 5, 1955

